Electrical contacting devices are used in a number of electro-mechanical applications to make and break electrical circuits. Typically, electrical contacting devices have two conductive surfaces and a contact member formed of a conductive material, wherein at least one of the conductive surfaces is attached to an electrical source. When the contact member is positioned such that it makes contact with both of the conductive surfaces, it electrically couples the two conductive surfaces, thereby making an electrical circuit. Conversely, when the contact member no longer makes contact with both conductive surfaces, then it no longer electrically bridges the conductive surfaces and the circuit is broken.
Electrical contacting devices are commonly used in switches such as a rheostat. In operation, mechanical or electro-mechanical means (e.g. thumbwheels, slides, toggles) are used to move the contact member in and out of contact with both of the conductive surfaces, thereby varying the electrical output of the switch. It is common in the design of switches to slide a contact member along either a linear or arcuate path, wherein the conductive surfaces are disposed at discrete locations along these paths. When the contact member reaches a point in the path where both of the conductive surfaces are disposed such that the contact member makes contact with both conductive surfaces, a circuit is made. It is also typical for some switches to have a stationary contact member, wherein the conductive surfaces translate along a linear or arcuate path, thereby forming electrical circuits in a like manner.
Another common feature in switches is the inclusion of a detent assembly within the switch. The purpose of the detent assembly is to provide a user of the switch with "detent feel," which is either tactile or aural indications of the positioning of the switch. Detent assemblies frequently employ a spring biased finger which moves along a path within the switch upon movement of the electrical contact member, and a wedge-shaped detent bump which is positioned at a location along the finger's path. When the finger makes contact with the detent bump, the finger resiliently retracts, thereby allowing the finger to travel past the detent bump. When the finger clears the detent bump, the resilient nature of the finger snaps the finger back to its initial, unretracted position. To the user of the switch, the contact between the finger and the detent bump produces a resistive force on the contact member that can be tactilely sensed by the user. In addition, when the finger clears the detent bump, the snapping action of the finger produces an aural indicator of the switch's position to the user as well.
Detent assemblies are commonly used to assist the user of the switch to find a discrete position of the switch. For example, a switch using a detent assembly for the purpose of indicating an on or off position would produce "detent feel" only when the switch is either in the "on" position or in the "off" position, and not at any other point. It is common for switches employing detent assemblies to be used when the switch is used as a mode selector. In this application, the switch allows the user of the switch to select various modes, wherein the user will experience "detent feel" as the switch is positioned such that one of the modes is selected.